Australian researchers find immune 'kill switch'

Updated
December 07, 2012 07:46:00

Melbourne Researchers have discovered why the body reacts the way it does when under stress from a severe infection. They've found what they're calling an immune system 'kill switch' that destroys blood stem cells - and they've been able to turn it off. The discovery could mean a faster recovery rate from blood infections and chemotheropy sessions.

TONY EASTLEY: For want of a better description we all apparently have an immune system 'kill switch'.

Melbourne researchers have discovered why the body reacts the way it does when under stress from a severe infection.

They've found that the immune system switch destroys blood stem cells, and they've also discovered how to turn it off.

The discovery could mean a faster recovery rates from blood infections and from bouts of chemotherapy.

Martin Cuddihy reports.

MARTIN CUDDIHY: Worldwide, sepsis or blood poisoning is one of the leading causes of death in the intensive care units of hospitals.

When someone develops the condition the body goes into shock and blood stem cells start dying.

SETH MASTERS: You can think about it like suicide. The cells know that they should die to try and get rid of the infection but if the infection is overwhelming as it is with sepsis, then we need them to stay alive to help fight any infection.

MARTIN CUDDIHY: Dr Seth Masters from the Walter and Eliza Hall Institute in Melbourne is part of a research team that's discovered the kill switch that tells cells when they should die.

Normally that's a good thing, except when there's a massive infection.

SETH MASTERS: You have to repopulate those immune cells somehow and these come from progenitor cells in the bone marrow and we think that this cell death pathway is something we can block to try and help the new cells regenerate to fight the infections better.

MARTIN CUDDIHY: So what does this cell receptor normally do?

SETH MASTERS: We are not entirely clear about that. We think that when a progenitor cell gets infected it'd be really bad if it stayed alive for too long cause it would pass that infection along to all of its daughters and sons.

So instead of staying infected, it just commits suicide and dies via this new pathway.

MARTIN CUDDIHY: Dr Masters is part of an international research team that's found blocking a certain cell receptor stops blood cells from dying.

The researchers hope the discovery could lead to a treatment for sepsis and a way to help boost the immune system of cancer patients undergoing chemotherapy.

SETH MASTERS: I think that probably the most likely avenue where it could be of use is in trying to help recovery from chemotherapy. That's a period during which we really need as many cells to mobilise out of the bone marrow into the periphery as possible to try and fight any potential infections that might be coming along.

And so we think that this cell death pathway might be stopping that from happening quickly and if we can inhibit it, we can make it go faster.

MARTIN CUDDIHY: Does that mean then that someone could be subjected to a more intense round of chemotherapy if this was to work and therefore you could boost their immune system following that round of chemo?

SETH MASTERS: Yeah, that does seem like a relatively attractive proposal. It is not something we have actually validated just yet but that would have to be on the cards if we can do some more research down those lines.

MARTIN CUDDIHY: The findings are published today in the medical journal Immunity.